Do Fish Perceive Anaesthetics as Aversive?

Letting fish choose their anaesthetics for better welfare: Aversive behaviours guide humane selection of anaesthetics

 Despite years of routine general use of many anaesthetic agents, within both scientific research and aquaculture, there is a paucity of information regarding their tolerance and associated behavioural responses by fish. A humane anaesthetic should work without inducing stress for the animal during the process. This study examined nine of the most commonly used fish anaesthetic agents, and performed preference tests using adult mixed sex zebrafish (Danio rerio) (Wik train). Video tracking software quantified swimming behaviour related to aversion for each anaesthetic at 50% of its standard recommended dose compared with clean water in a flow-through chemotaxic preference chamber. Study exposure was via predetermined Latin Square design and multivariate statistical analysis, with acid providing a positive control. Two agents were found not to induce aversive behavioural responses in zebrafish: etomidate and 2,2,2-tribromoethanol.


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